As a preventive measure against global warming, attention has been focused on efficient use of energy that biomass has. Of the biomass, plant-derived biomass energy has a nature of being so-called carbon neutral, since fixed carbon by photosynthesis from atmospheric carbon dioxide during the plant growing process, can be efficiently used, which means that atmospheric carbon dioxide will not increase in view of life cycle. Furthermore, also in view of oil-resource depletion and a rapid increase in the crude oil price, a biomass fuel has been expected to be a very promising petroleum-alternative energy.
Such use of biomass energy have been studied variously also in the field of transportation fuel. For example, if a fuel derived from an animal or vegetable oil can be used as a diesel fuel, the fuel is expected to play an efficient role in reducing a carbon dioxide emission due to synergetic effect with energy-efficiency of a diesel engine. As the diesel fuel using an animal or vegetable oil, fatty acid methyl ester oil (Fatty Acid Methyl Ester is abbreviated as “FAME”) is generally known. FAME is produced by subjecting a triglyceride, which is a general structure of animal and vegetable oils, to a transesterification reaction with methanol, with the aid of the function of e.g., an alkali catalyst.
However, in the process for producing FAME, as is described in patent document 1 below, it is necessary to dispose glycerin produced as a by product. In addition, cost and energy are required for washing generated oil. These are pointed out as problems.